ABSTRACT
It is essential for energy storage and conversion systems to construct electrodes and electrocatalysts with superior performance. In this work, ZnCo2S4@Ni(OH)2 nanowire arrays are synthesized on nickel foam by hydrothermal methods. As a supercapacitor electrode, the ZnCo2S4@Ni(OH)2 structure exhibits a specific capacitance of 1,263.0C g-1 at 1 A g-1. The as-fabricated ZnCo2S4@Ni(OH)2//active carbon device can achieve a maximum energy density of 115.4 Wh kg-1 at a power density of 5,400 W kg-1. As electrocatalysts, the ZnCo2S4@Ni(OH)2 structure delivers outstanding performance for oxygen evolution reaction (an overpotential of 256.3 mV at 50 mA cm-2), hydrogen evolution reaction (141.7 mV at 10 mA cm-2), overall water splitting (the cell voltage of 1.53 V at 50 mA cm-2), and a high stability for 13 h.
ABSTRACT
NiMoO4 is an excellent candidate for supercapacitor electrodes, but poor cycle life, low electrical conductivity, and small practical capacitance limit its further development. Therefore, in this paper, we fabricate NiMoO4@MnCo2O4 composites based on a two-step hydrothermal method. As a supercapacitor electrode, the sample can reach 3000 mF/cm2 at 1 mA/cm2. The asymmetric supercapacitor (ASC), NiMoO4@MnCo2O4//AC, can be constructed with activated carbon (AC) as the negative electrode, the device can reach a maximum energy density of 90.89 mWh/cm3 at a power density of 3726.7 mW/cm3 and the capacitance retention can achieve 78.4% after 10,000 cycles.
